Various fruit juices and beverages that contain fruit o components are popular because of their appealing taste and because they are perceived as being natural and nutritious. Commercially extracted and packaged fruit juices are more widely consumed than hand-squeezed juice primarily because commercial juice is much more convenient. However, it has been found that many consumers prefer the taste and texture of hand-squeezed juice over commercially processed juice. Accordingly, a principle object of the present invention is to commercially extract the edible components of a fruit in such a way that the resulting juice has a taste and texture similar to that of hand-squeezed juice.
Citrus fruits such as oranges and grapefruits basically consist of an outer colored peel (flavedo), an inner white spongy peel (albedo), a fibrous membrane just inside the albedo, and an inner meat portion formed in wedge-shaped segments that are separated by fibrous membranes extending radially from a stem. The stem is a pulpy core that typically contains several large and small seeds. The individual meat segments primarily consist of juice sacs, which are elongated teardrop-shaped bags that contain the fruit juice, that are held together by an epicuticular wax. The fruit's juice sacs and the juice from these sacs are generally considered to be the most desirable components for human consumption. The fruit's other components, such as the peel, membranes, stem, and seeds, are useful for other applications such as cattle feed.
It has been found that the method used to extract the edible components of a fruit greatly influences the taste, texture, and overall quality of the final product. During hand squeezing, the consumer either intuitively or because of physical limitations presses lightly on the fruit to extract the juice along with mostly ruptured juice sacs. Even though this juice is sometimes mixed with some shredded membranes and seeds, it is typically consumed almost immediately. In a commercial environment, it has been found that the less contact between the fruit juice and the fruit's undesirable flavor-containing components, the better tasting the juice product. This is believed to be because commercially processed juice is not consumed immediately and because it is generally exposed to considerable heat during pasteurization. When juice and undesirable flavor containing components such as seeds and membranes are intermixed and exposed to heat and time, the result does not taste like hand-squeezed juice.
Most production machinery used today for extracting juice from fruits can perhaps be most accurately characterized as fruit smashers. In general, these machines break the fruit into its various components and subsequently separate the juice by forceful screening. For example, the apparatus disclosed in U.S. Pat. No. 4,700,620 and leased by the FMC Corporation mashes the entire fruit, which ruptures essentially all of the juice sacs, while abrading and commingling the fruit's components as the juice is filtered therefrom.
Another type of apparatus used in the commercial juice extracting industry can be characterized as a reamer, examples of which are disclosed in U.S. Pat. Nos. 2,737,989 to Wurgaft and 4,479,424 to Carroll. In a basic reaming operation, the fruit is first cut in half, followed by pressing a reaming element into the exposed fruit meat, which ruptures the juice sacs and releases the juice. However, the reaming element also squeezes the fruit's peel, membranes, and seeds and thereby releases the undesirable flavor elements found in these fruit components, which results in poor tasting juice. In addition, the fruit's radial membranes tend to fold over onto themselves when the reamer both presses and rotates against them which makes it extremely difficult for the reamer to extract the fruit meat deep within the fruit half. Because of the need for high juice yields in commercial processes, reamers are usually pressed very hard into the fruit which further aggravates the problem.
Another type of commercial fruit meat extraction method and apparatus is generally referred to as a peeler, an example of which is disclosed in U.S. Pat. No. 3,700,017 to Vincent et al. In such a system, hand oriented fruit is placed between two spikes that are sharply shoved into the stem ends of the peel. The spikes are then rotated to spin the fruit past knives that move laterally across the fruit circumference to cut the peel from the meat. It has been found that slicing the peel into narrow strips in this fashion releases a substantial amount of undesirable peel oil from the peel which contaminates the fruit meat. In addition, peeling techniques typically require a strong spike/peel connection to maintain adequate peeling torque. This in turn requires a speed-limiting and therefore costly hand-orienting step to insert the spike near the fruit stem where the peel thickness is greatest. Non-spherical fruits such as those dented during shipping further complicate a peeling operation. Specifically, at reasonable production rates, either some peel is left on the meat or some of the meat is removed with the peel, thereby creating a tradeoff between contamination and meat yield. Ultimately, peeled balls of fruit meat must be further processed to separate the juice from the membranes, stems, and seeds. A belt press may be used for this purpose wherein the belts act as both a transporter of fruit balls and as a screen for filtering the juice from the fruit ball's membranes, stem, and seeds. Here again, essentially all of the juice sacs are ruptured.
Another type of known extraction system involves using various chemical baths such as alkali/phosphate and acid to dissolve the circumferential and sectional membranes from peeled fruit balls. Two examples are disclosed in U.S. Pat. No. 4,560,572 to Watanabe and U.S. Pat. No. 4,139,651 to Sekiguchi. However, it is believed that these systems would be unattractive for making juice in a commercial environment because of the high costs associated with the necessary chemicals and the inherent throughput rate limitation. In addition, it is believed that the chemicals used in these processes would have a major adverse effect on the fruit juice's taste and texture.
Still another extraction technique involves using high pressure fluid jets, examples of which include U.S. Pat. Nos. 1,982,741 to Keenan; 4,294,861 to Ifuku et al.; and 4,300,448 to Hyashi et al. Generally, this type of system includes the steps of orienting the fruit so that it can be cut in half perpendicular to the stem, and placing the exposed fruit meat in front of a fluid jet nozzle. High pressure fluid emitted from the nozzle blasts the fruit meat from the peel. Although unruptured juice sacs can be obtained by using this process, the fruit's sectional membranes tend to fold over onto themselves and thereby impede the fluid jet's ability to remove the meat deepest within the peel. As a result, fluid pressures high enough to strip away the membranes as well as the juice sacs are required. At such pressure, the fluid ruptures many of the juice sacs and also tend to shred the fruit's sectional membranes. The juice slurry which results cannot easily be cleaned of membrane contaminants without also eliminating the desirable unruptured juice sacs. In addition, the orienting step is a critical process speed limiter because there is believed to be no reliable automated way to orient a substantially round citrus fruit.
In light of the above, the principal object of the present invention is to extract juice sacs and juice from a fruit with as little membrane and peel oil contamination as possible such that even after further processing, packaging and storage, the resulting juice product will have a taste similar to that of hand-squeezed juice.
Another principal object of the present invention is to extract fruit juice sacs from a fruit without rupturing a substantial portion of the fragile juice sacs and without shredding the fruit's sectional membranes so that the juice sacs can be readily separated from the membranes.
Yet another object of the present invention is to achieve high juice sac and edible fruit meat yields in a commercial environment.
Still another object of the present invention is to extract a portion of the available whole juice sacs from a fruit without disturbing the fruit's seeds to avoid a further process step of separating the seeds from the whole juice sacs.